نتایج جستجو برای: ultramafic rocks
تعداد نتایج: 22653 فیلتر نتایج به سال:
An introduction to the Bouguer anomaly map of Finland is presented. Anomaly sources from surface to upper mantle are discussed both qualitatively and quantitatively. Related density variations are reviewed. The article is based on gravity data from the Finnish Geodetic Institute supplemented by petrophysical and gravity data from the Geological Survey of Finland. The Finnish Geodetic Institute ...
Talc schist deposits are reported in central Cameroon region, and different alteration zones were determined depending on differences related to the texture color of host rock. For purpose determining mineralogical physicochemical characteristics talc schist, a total 45 samples from sites studied collected analyzed using an array physico-chemical methods. mainly composed variable amount associa...
Olivine is a major mineral in ultramafic and mafic rocks. Due to the higher Mg/Fe partition coefficient of olivine than coexisting phases, occurrences Mg–poorer grains, especially with Mg#[= Mg/(Mg + Fe2+)] = 0.2–0.6, are rarely reported, thus, their spectroscopic data limited. Fe–rich phenocrysts showing compositional zoning Mg# ~ 0.5 (core) 0.3 (rim) microphenocrysts 0.4 0.2 occur basaltic tr...
Ophiolites of the Zagros orogenic belt are part of the Tethys ophiolites, because of their geographical locations and link the Middle East ophiolites and other Asian ophiolites (e.g. Pakistani and Tibetan) to the Mediterranean ophiolites (e.g. Troodos , Greek and East European). The nature of the Harsin- Sahneh ophiolite (Kermanshah) traditionally identified as one of the Mesozoic southern bran...
The volcanic Rooiberg Group represents the earliest phase of Bushveld-related magmatism and comprises, in some areas, the floor and roof rocks of the mafic–ultramafic intrusive units of the Bushveld Complex. The lower to middle Dullstroom Formation is composed of two interbedded series of low Ti and high Ti volcanic strata, which are predominantly basaltic andesites. Volcanic units above these ...
The rare earth elements (REE) are composed of the Lanthanide Series of 15 elements with atomic numbers (57) through (71) and yttrium (39). Because of their geochemical behavior, REE rarely form their own minerals and more commonly are found incorporated within the structure of other minerals. There is growing concern over the economical availability of REE because of their diverse and expanding...
نمودار تعداد نتایج جستجو در هر سال
با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید